A Government spokesman rejected a proposal in the House of Commons yesterday that Britain introduce a resolution in the United Nations calling for a humanitarian investigation of the condition of Jews in Arab countries as well as of Arabs in Israel-occupied territory. The proposal was made by Sir Ian Orr-Ewing (Conservative). Goronwy Roberts, Minister of State at the Foreign Office, replied that the Government’s position was made clear by its vote in favor of a Security Council resolution calling for an investigation of Arab conditions in the occupied territories. Israel has refused to permit such an investigation unless a similar one is carried out in Arab countries where Jews are reportedly imprisoned without trial and generally mistreated. The Arabs refuse to allow it.